TROUBLESHOOTING

 

 

 

 

 

 

DIAGNOSTIC TABLE

 

 

 

 

 

DS 1 (Red)

DS 2 (Green)

Error/Condition

Comments/Troubleshooting

Simultaneous

Simultaneous slow

Normal operation

No fault

slow flash

flash

 

 

 

 

 

 

 

 

Simultaneous

Simultaneous

Normal operation with call

Normal operation

fast flash

fast flash

for heat

 

 

 

 

 

 

 

Slow flash

On

Open limit switch

Verify continuity through rollout switch circuit

 

 

 

 

 

Off

Slow flash

Pressure switch stuck

Pressure switch stuck closed. Check switch func-

 

 

closed/open

tion, verify inducer is turning off.

 

 

 

Pressure switch stuck open. Check pressure switch

 

 

 

function and tubing. Verify inducer is turning on and

 

 

 

pulling sufficient vacuum to engage switch.

 

 

 

 

 

Alternate

Alternate slow flash

External lockout (retries)

Failure to sense flame is often caused by carbon

slow flash

 

 

deposits on the flame sensor, a disconnected or

 

 

 

shorted flame sensor lead or a poorly grounded

 

 

 

furnace. Carbon deposits can be cleaned with em-

 

 

 

ery cloth. Verify sensor is not contacting the burner

 

 

 

and is located in a good position to sense flame.

 

 

 

Check sensor lead for shorting and verify furnace

 

 

 

is grounded properly.

 

 

 

 

 

Slow flash

Off

Flame sensed with gas

Verify the gas is operating and shutting down prop-

 

 

valve de-energized

erly. Flame in burner assembly should extinguish

 

 

 

promptly at the end of the cycle. Check orifices and

 

 

 

gas pressure.

 

 

 

 

 

On

Slow flash

Open rollout switch

Verify continuity through rollout switch circuit.

 

 

 

 

 

On

On

Module – internal fault

Module contacts for gas valve not operating or

 

 

condition

processor fault. Reset control, if condition persists,

 

 

 

replace module.

 

 

 

 

 

Slow flash

Fast flash

Low flame sense current

Low flame sense current is often caused by carbon

 

 

 

deposits on the flame sensor, a poorly grounded

 

 

 

furnace or a mis-aligned flame sense probe.

 

 

 

Carbon deposits can be cleaned with emery cloth.

 

 

 

Check or improve furnace and module ground.

 

 

 

Verify sensor is located in or very near flame as

 

 

 

specified by the appliance manufacturer.

 

 

 

 

 

Fast flash

Slow flash

Grounding or reversed

Verify the control and furnace are properly ground-

 

 

polarity

ed. Check and reverse polarity (primary) if incorrect.

 

 

 

 

 

Alternate fast

Alternate fast flash

Module ignitor contact

Fault code indicates the module ignitor contacts

flash

 

failure

are not functioning properly. Replace module.

 

 

 

 

 

7

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Image 7
White Rodgers 21D83M-843 Simultaneous Simultaneous slow, Slow flash Flash Simultaneous, Fast flash, Off Slow flash
Page 6 Page 8

21D83M-843 specifications

The White Rodgers 21D83M-843 is a versatile and reliable thermostat designed for both residential and light commercial use. With its advanced features and user-friendly interface, it continues to be a popular choice among homeowners and HVAC professionals alike.

One of the main features of the 21D83M-843 is its ability to provide precise temperature control. This thermostat utilizes an electronic sensor that allows for accurate monitoring and adjustment of indoor climate, ensuring comfort while optimizing energy efficiency. The device supports multi-stage heating and cooling systems, including conventional and heat pump configurations, making it adaptable to various HVAC systems.

The 21D83M-843 showcases a clear and easy-to-read display, providing users with essential information in real-time. The backlit screen ensures visibility, even in low-light conditions. Additionally, the intuitive user interface simplifies programming and operation, allowing users to set schedules and adjust settings with ease.

Programmable settings are a highlight of the 21D83M-843. Homeowners can enjoy the benefits of scheduling their heating and cooling systems to align with their daily routines, which leads to significant energy savings. The thermostat allows for multiple daily temperature changes, ensuring that the home environment remains comfortable while energy costs are minimized.

One of the standout technologies incorporated in the 21D83M-843 is its adaptive intelligent recovery feature. This innovative technology learns the home’s heating and cooling patterns, allowing the thermostat to anticipate the desired temperature and reach it at the right time. This not only enhances comfort but also further contributes to energy efficiency.

Another notable characteristic is the thermostat’s durability and compatibility with various HVAC systems. It is designed to work seamlessly with 24-volt heating and cooling systems, making it suitable for a wide range of applications. Its robust construction promises long-lasting performance, providing peace of mind to users.

In conclusion, the White Rodgers 21D83M-843 is an outstanding choice for those seeking a reliable, energy-efficient thermostat. With its precise temperature control, user-friendly interface, programmable features, and advanced technologies, it stands out in the crowded thermostat market. Whether for residential or light commercial use, the 21D83M-843 effectively meets the demands of modern heating and cooling needs while promoting comfort and efficiency.
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